One technique that can be used to enhance performance, aesthetics or other characteristics of fibers or fabrics involves providing a material or agent, for example a fragrance, in small microcapsules that can then be applied to the desired fiber or fabric. Microcapsules typically comprise a core, which contains at least one material or agent, surrounded by a thin wall. The material or agent can be released when microcapsule walls rupture or otherwise disintegrate in response to appropriate stimuli, such as temperature, pressure or physical contact with the wearer's skin.
Microcapsules commonly are applied to textile materials using agents called binders. A number of approaches can be used to apply microcapsules to textile materials using binders. For example, in one approach, a textile material is placed in a bath containing both microcapsules and binders followed by heating or drying of the textile material. Other approaches involve contacting textile materials with binders before adding microcapsules. Yet other approaches involve coating microcapsules with binders prior to applying them to textile materials. Within any of these approaches, the degree to which microcapsules adhere to a particular textile material is typically a function of not only the process used but also of the binder material or materials selected. Accordingly, the choice of binder materials or binder system components can be of particular importance in the successful application of microcapsules to textiles.
It can be challenging to incorporate textiles containing microencapsulated materials into clothing and apparel. For example, a fabric containing microencapsulated materials may not have good washfastness or durability, meaning the fabric quickly loses the ability to retain the characteristic(s) or effect(s) provided by the microencapsulated material(s) through extended use and/or multiple washing cycles. In this regard, use of a particular binder may result in significant variability when applied to different fabric types and structures, i.e., it may provide good washfastness in some applications and poor washfastness in others.
In addition to issues relating to washfastness or durability, fabrics containing microcapsule finishes may have poor micro dispersability, meaning that the microcapsules have a tendency to coagulate in bunches, thereby increasing the average unit size deposited and decreasing the ability of the microcapsules to penetrate and bond in a fabric structure. Fabrics containing microcapsules may also contain a high ratio of binder material to microcapsules, which can add stiffness and detract from the tactility of the fabric. In addition, a particular binder composition may contain toxic components that are not easily disposed of at a processing facility. Alternatively, a particular microcapsule/binder combination may not be compatible with other ingredients, such as softeners, that are commonly used in the apparel fabric industry. Finally, a given system of microcapsules and/or binder materials may present particular processing difficulties, such as microcapsule wall polymers that do not have sufficient thermal stability to withstand common textile processing or binder systems that require extended high temperature cure times that are not efficient in standard processing facilities. Accordingly, in applying microcapsules to textile materials, a need exists for binder components and systems that can address one or more of these challenges.